In the given part of a circuit, the potential at point $B$ is zero. Then, the potentials at $A$ and $C$ respectively, are

Which of the following is the unit of mobility of a electron in a conductor?

The time required to raise the temperature 3 litre of water from $0^{\circ} \mathrm{C}$ to $80^{\circ} \mathrm{C}$ by a heater operated under 200 V having resistance of $50 \Omega$ is [specific heat capacity of water is $4200 \mathrm{~J} \mathrm{~kg}^{-1} \mathrm{~K}^{-1}$ ] [density of water $=1000 \mathrm{~kg} / \mathrm{m}^3$ ]

The current density in a circular wire is given by $J(r)=\left(1 \times 10^5 \mathrm{~A} / \mathrm{m}^3\right) r$, where $r$ is the radial distance and the wire's radius is 2 mm . If the potential applied across the wire is 70 V , then the energy consumed by the wire in 1000 s is